Asphalt emulsion



July 18, 1961 E. w. MERTENS ET AL 2,993,003

ASPHALT EMULSION Filed Sept. 25, 1957 O In Illlllll DEMULSlBlLl"['Y- l l 050 0.60 0.70 POLYGLYCOL ETHER OF ALKYL PHENOL. PER CENT V|SCOSITY (0.155 PER CENT KOH) o 00 a) 40m :l:!S 'd zzl .LV ALISODSIA INVENTORS EDWARD W. MERTENS JAMES R%/?/ HT ATTORNEY 2,993,003 Patented July 18, 1961 2,993,003 ASPHALT EMULSION Edward W. Mertens and James 'R. Wright, El Cerrito, Calif., assignors to California Research Corp'oration, San Francisco, 'Calif., a corporation of Delaware Filed Sept. 25, 1957, Ser. No. 686,194 ZClaims. (Cl. 252-311.5)

This invention relates to a new and improved asphalt emulsion. More particularly, the invention is concerned with high residue anionic asphalt emulsions having improved viscosity characteristics.

Asphalt, or bitumen as it is also called, is useful in a wide variety of applications. Illustrative applications include its use in the paving of road surfaces, waterproof coatings and protective coatings in general, as well as the impregnation of fiber-containing materials such as paper or felt.

Generally speaking, asphalt is employed in applications of the above type mainly in three forms of liquids. In perhaps its oldest form it is melted by heating and applied as a molten mass. It is also combined with volatile organic solvents to provide liquid solutions of desired viscosity known as cut-back asphalts. Asphalt is also emulsified with water and used in the form of liquid as phalt emulsions. This last form, to which the present invention relates, has several advantages over molten asphalt and cut-back formulations. The asphalt is maintained in liquid form during application without the need for expensive heating equipmentand at the same time the high costand fire hazards involved in the use of organic solvent are avoided. a

Asphalt emulsions are usually prepared by mixing the asphalt with an aqueous solution of an alkali metal hydroxide such as sodium or potassium hydroxide to saponify certain high molecular weight carboxylic acids in the asphalt. Such acids may occur naturally in the asphalt or they may be added where the natural acid content is unsatisfactorily low. The soaps thus formed serve as emulsifying agents to produce asphalt emulsions when the asphalt and water of the aqueous solution are mixed to gether. These asphalt emulsions are classified as anionic in nature because the alkali metal soap emulsifying agents bear a negative charge and are attracted to the anode or positive pole in solution.

A number of special properties are desirable in the so-called quick breaking asphalt emulsions of the present type. One of the most important and fundamental properties is a low viscosity in combination with a high residue. Since asphalt emulsions are usually applied by machinery, it is important that the emulsion flows freely. Low viscosity emulsions are also usually more penetrating and, therefore, more eifective in theusual coating and impregnating applications. It is particularly desirable that a high residue be maintained where possible along with the low viscosity'of the asphalt emulsion in order to avoid the necessity for handling unduly-large amounts of emulsion in a given application. The stabilities of asphalt emulsions are also important factors because it is highly desirable that separation of the asphalt and aqueous phases and increased viscosities be avoided When the emulsions are allowed to stand as during storage. At the same time, it is essential that the emulsion separate rapidly on contact with the material to be coated or impreg-v metal hydroxide.

nated such as aggregate, felt and paper. Suitable asphalt emulsions should likewise quickly demulsify in the presence of electrolytes such as calcium chloride.

It has now been found that a greatly improved high residue asphalt emulsion of low viscosity is obtained in the composition comprising an anionic asphalt emulsion and from 0.05 to 2.0 percent by weight of polyethylene glycol ether of alkyl phenol having from 5 to ethylene glycol units and from 6 to 22 carbon atoms in the alkyl group.

The superior new asphalt emulsions of the invention possess remarkably low viscosities compared to similar emulsions which do not contain the polyglycol ether of alkyl phenol. The emulsions are characterized by surprisingly high residues considering the low viscosities.

These important properties permit the most effective utilization of the emulsions in coating and impregnating applications. The emulsions also have excellent stability under storage conditions and do not increase unduly in viscosity or separate on standing. Their demulsibility and quick breaking properties are also outstanding.

According to the present invention, suitable anionic asphalt emulsions are prepared by mixing hot molten asphalt with a hot aqueous solution of an alkali metal hydroxide having a concentration within the range of from about 0.01 to about 2.0 percent by weight alkali For present purposes, potassium hydroxide, particularly in concentrations of 0.05 to 0.30, is preferred. Usually from 40 to of asphalt is employed with from 20 to 60% of water.

The polyethylene glycol ether of alkyl phenol is employed in the anionic asphalt emulsion of the invention in any proportion sufiicient to lower the viscosity of the emulsion. Preferably from about 0.05 to about 2.0 percent by Weight is used based on the total emulsion. The

. polyglycol ether of alkyl phenol may be added to either the aqueous metal hydroxide solution or the asphalt prior to mixing; It may also be added to the anionic asphalt emulsions after they are formed. However, the most effective reduction in viscosity is obtained by adding the polyglycol phenyl ether to the aqueous alkali metal hydroxide solution prior to mixing with the asphalt.

Suitable polyglycol alkyl phenyl ethers contain from 5 to 60 ethylene glycol units and from 6 to 22 carbon atoms in the alkyl group, as mentioned above. They are illustrated by the formula, HO(CH CH O),,XR, wherein n is the number of glycol units, X is a phenylene group and R is representative of the alkyl groups. Illustrative polyglycol alkyl phenyl ethers include the polyethylene glycol ether of octyl phenol having 5 ethylene glycol units, the polyethylene glycol ether of octyl phenol having 20 ethylene glycol units, the polyethylene glycol ether of octyl phenol having 30 ethylene glycol units, the polyethylene glycol ether of dodecyl phenol having 20 ethylene glycol units, the polyethylene glycol ether of octadecyl phenol having 40 ethylene glycol units, the polyethylene glycol ether of docosanyl phenol having 60 ethylene glycol units, the polyethylene glycol ether of di- ,dodecyl phenol having 60 ethylene glycol units, etc.

Presently preferred are the polyethylene ethers of alkyl phenols containing an average of from 10 to 40 polyethylene glycol units and from 8 to 14 carbon atoms in the alkyl group.

A wide variety of asphalts are suitable in the prepara- 'tion of the superior new asphalt emulsion according to this invention. Asphalts which normally contain suflicient high molecular weight carboxylic acids to provide emulsions upon saponification of the acids with aqueous alkali metal hydroxide solutions are preferred. It is possible, however, to increase or decrease the amount of droxide emulsifying base is mixed with the asphalt at a temperature in the range of from about 120 .to 180 F.

-where colloid mills are employed the temperatures may be raised to 300 F. or more. It is essential that the asphalt be in a molten state prior to mixing. Usually, temperatures of around 300 F. are sufficient, but the exact temperature will depend on the softening point of the particular asphalt employed in preparing the emulsion.

In a further illustration of the greatly improved high residue anionic asphalt emulsions of the invention, a series of emulsions was prepared and tested, as outlined in the following paragraphs.

All of the emulsions were prepared in 2,500 gm. quan tities in a steam heated, stainless steel vessel equipped with a 1,725 r.p..m. stirrer, temperature gauge, condenser and electrically heated asphalt reservoir. The aqueous phase consisting of distilled water, alkali metal hydroxide and the specified polyethylene glycol ether of alkyl phenol is made up in the vessel and brought to a temperature of 160 F. with continuous stirring. Simultaneously, the asphalt is put into the asphalt reservoir and brought to a temperature of 250 F. When both the aqueous and asphalt phases are at the desired temperatures, the asphalt is added to the aqueous phase over a three-minute period. Following an additional 30 seconds stirring period, the emulsion is withdrawn into a one-gallon glass jar. The glass jar is covered and placed in a 120 F. oven for over-night storage prior to testing.

The asphalt employed in the tests was a typical Venezuelan asphalt of 200 to 250 penetration. The emulsions were formulated with 58% by weight asphalt, potassium hydroxide, polyethylene glycol ether alkyl phenol and the balance water, as indicated in the table below. The viscosity in .seconds Saybolt Furol for 60 mls. at 122 F. and the demulsibility were determined accord ing to the Standard Methods of Testing Emulsified Asphalts, ASTM designation D:244-55. The demulsibility of a particular emulsion is the percentage by weight of the asphalt present that fails to pass a No. 14 wire cloth when a 100 gm. sample of the emulsion {is mixed with 35 mls. of 0.02 N calcium chloride solution. The residue test determines the percent by weight of residue which remains after a 25 gm. sample of the emulsion is heated until all of the water is evaporated. The polyethylene glycol ether of alkyl phenol employed in the test was of four types. Two were polyglycol octyl phenol ethers having about 20 and about 30 ethylene glycol units, illustrative of the more satisfactory polyglycol phenol ethers in the compositions of this invention. The other two polyglycol alkyl phenol ethers were those having only about 1 and about 3 ethylene glycol units and were employed to illustrate the effect of compositions on a g lky ph n po y e et rs f u ab -y low number of ethylene glycol units.

Table Variable Components Properties Particle Size .Storage Stability, Polyglycol Demulsi- -1 Week at 160 F.

Alkyl Viscosity, bility Residue, Type Phenyl SSF, at (0.02 N Percent a Ether, F. CaClz) *Predomi- Demulsi- Percent Range nant Viscosity bility,

- Percent 0. 255 98 56. 8 0. -7 4 226 98 0.025 462 96 57. 2. 0. 5-6 4 '603 97 0.05 148 94 57. 2 0. 5-4 '3 175 -98 0. 075 "126 92 57. 2 0. 5-5 3 319 98 (1) .0. 480 96 56. 4 0. 5-0 3 '158 96 0. 589 97 57. 6 0. 5-8 3 604 97 0.35 1502 98 57. 2 0. 5-7 2.5 435 90 0. 50 701 100 57. 6 0. 5-.-5 2. 5 I 213 62 0.05 386 99 57.6 0. 5:6 2. 5 111 40 -0. 80 75 100 57. 6 197 38 i0. 00 648 '97 5618 1-8 3 320 100 0. 017 314 97 57. 2 1..5 .3 193 97 0.035 225 97 57. 2 1-4 3 107 86 1(2) 0.05 .235 96 57 2 1-4 '12. 5 46 94 0. 07 77 84 56. 4 1:3 2 .40 85 0; 14 24 79 57.6 -1-5* 1.5 14 65 0. 24 25 81 57. 2 1-6 3 16 e 62 0. 0 470 95 56. 8 72-5 1 .680 97 0. 025 '103 86 56:8 Va-5 3 200 92 0. 050 108 89 57. 2 36-6 3 92 .89 0. 075 40 88 56.8 -4 1 71 86 0.10 42 84 57. 2 V-fi 52 82 (3), 0. 20 36 57 57. 6 36-3 '1 .48 66 0. 35 58 97 56. 4 BrOken 49 98 0. 16 63 57.2 95-4 1 19 68 0. 19 56 56. 35 54-7 2% .21 65 0. 24 63 57. 2 r 7 3 26 .00 1.00 '33 17 58.0 6 '3 18 7 34 0. 0 88 72 56. 8 .1-7 4 215 1 100 0. 025 437 82 57. 2 1:5 .3 3. 3 .93 *0. 050 319 82 66. 4 1-5 3 224 92 0. 075 810 88 56. 8 1-7 3 .418 '99 0. 10 674 88 66. 8 1-5 3 414 97 (4) 0.20 569 8,5 56. 8 -L-7 4 327. 95 0. 35 .788 85 56. 8 1-7 3 333. 97 0.50 474 99 57.0 Broken Broke 104 97 p.65 149 99 58. 8 .Broken Broken Broken Broken .0. 80 96 58. 0 :Broken Broken Broken Broken =1 00 124 100 58. 0 Broken Broken 'Broken Broken (1) Polyethylene glycol other of octylphenol with an averageof. about lglycol group.

(2) Polyethylene glycol ether of octylphenol with an average of aboutBO glycolgroups. .(3) Polyethyleneglycol ether of octylphenol-with an average of about-20 glycol groups.

(4) Polyethylene glycol ether of octylphenol with an average of about 3 glycol groups.

The above test results show that the surprisingly improved anionic asphalt emulsions containing polyglycol alkyl phenyl ether in accordance with the invention have much lower viscosities than corresponding emulsions which contain no polyglycol alkyl phenyl ether. The improvement of the asphalt emulsions with the polyglycol alkyl phenyl ethers according to the present invention is particularly remarkable in view of the fact that other closely related asphalt emulsions of diflerent ethers and proportions have unsatisfactorily high viscosities. The emulsions according to the present invention are also seen to have unusually high residues considering the low viscosities. The combination of these two important properties in the emulsions of the invention means that they are most effective in coating and impregnating applications. Another superior characteristic of the present emulsions which is apparent from the above test results resides in the excellent stability of the emulsions under storage conditions, especially at the customary high temperatures of 120 F. and above. There is little or no increase in the viscosity of the emulsion on standing. Furthermore, it is seen that the emulsions do not tend to separate when allowed to stand for considerable periods of time.

In further illustration of the superior new anionic asphalt emulsion of the invention, the test data of the above table was plotted to give the graph of the accompanying drawing. The graph shows that when the polyglycol alkyl phenyl ether (3) is employed in the specified proportions according to the present invention, a remarkable improvement is obtained in the production of low viscosity high residue asphalt emulsions.

We claim:

1. An improved high residue asphalt emulsion of low viscosity consisting essentially of an anionic soap asphalt emulsion and from 0.05 to 2.0 percent by weight of polyethylene glycol ether of alkyl phenol having from 110 to ethylene glycol units and from 8 to 14 carbon atoms in the alkyl group, said ether being suflicient to lower the viscosity of the emulsion and said anionic soap asphalt emulsion being prepared by mixing from 40 to 80 percent by weight of molten asphalt with from 20 to percent by weight of aqueous solution of irom about 0.05 to about 0.30 percent by weight of potassium hydroxide so as to saponify high molecular weight carboxylic acids in the asphalt, the aforesaid proportions being based on the total asphalt emulsion.

2. An improved high residue asphalt emulsion of low viscosity consisting essentially of an anionic soap asphalt emulsion and from 0.05 to 2.0 percent by weight of polyethylene glycol ether of octyl phenol having an average of approximately 30 ethylene glycol units, said ether being sufiicient to lower the viscosity of the emulsion and said anionic soap asphalt emulsion being prepared by mixing from 40 to percent by weight of molten asphalt with from. 20 to 60 percent by weight of aqueous solution of from about 0.05 to about 0.30 percent by weight of potassium hydroxide so as to saponify high molecular weight carboxylic acids in the asphalt, the aforesaid proportions being based on the total asphalt emulsion.

References Cited in the file of this patent UNITED STATES PATENTS 1,970,578 Schoeller et al Aug. 21, 1934 2,635,055 Figdor Apr. 14, 1953 2,706,688 Sommer et al. Apr. 19, 1955 2,789,917 Hardman et al. Apr. 23, 1957 OTHER REFERENCES The American Perfumer and Essential Oil Review; article by Griflin; May 1955; pp. 26-29.

Atlas Guide to the Use of Sorbitol and Surfactants in Cosmetics; pub. by Atlas Powder Co., 1956, p. 31. 

1. AN IMPROVED HIGH RESIDUE ASPHALT EMULSION OF LOW VISCOSITY CONSISTING ESSENTIALLY OF AN ANIONIC SOAP ASPHALT EMULSION AND FROM 0.05 TO 2.0 PERCENT BY WEIGHT OF POLYETHYLENE GLYCOL ETHER OF ALKLY PHENOL HAVING FROM 10 TO 40 ETHYLENE GLYCOL UNITS AND FROM 8 TO 14 CARBON ATOMS IN THE ALKYL GROUP, SAID ETHER BEING SUFFICIENT TO LOWER THE VISCOSITY OF THE EMULSION AND SAID ANIONIC SOAP ASPHALT EMULSION BEING PREPARED BY MIXING FROM 40 TO 80 PERCENT BY WEIGHT OF MOLTEN ASPHALT WITH FROM 20 TO 60 PERCENT BY WEIGHT OF AQUEOUS SOLUTION OF FROM ABOUT 0.05 TO ABOUT 0.30 PERCENT BY WEIGHT OF POTASSIUM HYDROXIDE SO AS TO SAPONIFY HIGH MOLECULAR WEIGHT CARBOXYLIC ACIDS IN THE ASPHALT, THE AFORESAID PROPORTIONS BEING BASED ON THE TOTAL ASPHALT EMULSION. 